Generally, removable wheel covers on passenger and other vehicles are held in place by a circular, continuous retention ring made of hard, durable wire rod stock that seats inside a plurality of peripherally spaced retention teeth or fingers generally formed in an integral manner with the wheel covers, particularly plastic wheel covers. The teeth engage an inwardly facing, continuous, circular surface of the wheel's rim under substantial force provided by the retention ring, i.e., the ring has a diameter that is sized to force the integral teeth outwardly such that they firmly engage the inwardly facing surface of the wheel's rim.
Car manufacturers usually provide a flat edge tool for insertion between the edge of a wheel cover and the wheel rim to pry the cover from the wheel. Such devices can nick, bend and even break the covers in an effort to remove the covers from the wheel rim, as the force on the integral teeth of the cover in engaging the inner surface of the rim, as provided by the retention ring, makes the cover removal process difficult. It can be appreciated that such a retention ring has to exert a substantial force on the wheel cover in order to sustain retention of the cover in the wheel under hazardous and rough road conditions. Otherwise, wheel covers would easily come loose and often be lost to the owners of the motor vehicles.
A further concern with the use of prying devices is the possibility of personal injury, i.e., in endeavoring to force a flat edge tool between a wheel cover and wheel, the tool can slip and injure the hand of the user of the tool.
Another concern involves the wear of the plastic retention teeth that can occur with repeated removal from and insertion of the wheel cover into a wheel rim. Over time, such wear reduces the ability of the retention teeth to retain the cover in the wheel.